你我干净的不像话
[nĭ wŏ gān jìng de bù xiàng huà]
This implies 'You and I are so pure or clean as to be unbelievable.' It often refers to a relationship that is exceptionally simple, sincere, and untroubled by complex emotions or issues, sometimes sarcastically suggesting that nothing happened between two people even though there was some kind of interaction.